Lens for vehicle lamps



I "Oct. 23, 1928.

w. DA RYAN LENS' FOR VEHICLE LAMPS Fi led Dec. 27, 19:25

'A TTOM INVENTOR Warn 319x27 Km.

BY a q g g Patented Oct.- 23, 1928.

UNITED- STATES mrlzlv'r OFFICE.

LENS r03 VEHICLE 13AMPS.

'Application filed December 27, 1926.. Serial No. 157,197.

My invention relates to improvements in ,headlights, and is particularly concerned lateral illumination of sufficient intensity to enable the driver to see curbs, ditches, road with improvements in headlights for automotive vehicles.

The objects of my invention are First, to provide a headlight that is substantially non-glare but which, at the same .time, provides adequate illuminationnot .only in the immediate foreground, but also at a considerable distance ahead of the vehi-' cle carrying the headlight, and also provldes signs, etc.;

Second, to provide a headlight, such as described, that is simple in construction and economical to manufacture; and

Third, to provide a headlight having the characteristics set forth above that embodies a novel'type of lens, or closure;

. Other objects of my inventionwill appear as this description progresses, reference being had to the.accompanying drawings,- inwhich ing a part of my improved headlight.

Figure l is a front viewof the lens form 2 is a horizontal section therethrough on the line-22 of Fig. 1, and showing, inaddition, the reflector forming a part of my improved headlight. Fig. 3 is a vertical section taken on the line 33 of Fig. 1. Fig. 4 is an enlarged sectional detail taken on substantial ly the line 22 of Fig. 1, but looln'ng inthe opposite direction from that in which the section inFig. 2 is taken. 1

The reflector 10 of my improved headlight is preferably of the form described and claimed in-my co -pending application, Serial No. 88,911, filed February 17, 1926, but may, if desired, be given other forms and characteristics, although it should, in'generah have the characteristics of the reflector referred 'to as being described in my previously filed application. w This invention relates particularly to a lens comprising means for spreading some of the light from the side portions of the beam toward the central portion thereof so as to im-- prove the light distribution in the central portion of the beam. At the same time, by proyidingprismatic surfaces adapted to refract a large portionof the light from the 8 source for spreading it over the foreground immediately in front of the vehicle and also into the sides of the road so as to reduce the contrast between the illumination of areas ly bulging portion 11, substantially co-extensive with the mouth of the reflector, that is approximately in the form of a flattened conle having a rounded apex 11 and provided wit 1 a marginal, rearwardly extending.

flange 12 that is preferably sand blasted or otherwise adapted to' diffuse all light falling thereon.

A series of prisms extends across the portion 11 of the lens, being formed upon the inner side thereof, and this series of prisms is divided into the two side groups 14 and 15 and the central group 16. The prisms of each group, with theexception of those of the central group, comprise aconvex face 17 anda flat face 18. All of the flat faces 18 are substantially parallel with the axis of the lens, although they ma be slightly inclined to vfacilitate the manu acture of the lens.

While'the convex faces 17 of the prisms do act upon the direct light from the source 13. to tend to bend this v light toward the axis of the beam, theprincip-al function of these convex faces is to direct the light reflected from the reflector 10 into the centralportionof the beam in order to increase the intensity of that portion. The flat faces 18 intercept relatively little of 'the light reflected from the 3 reflector but receive most of the direct light from the source 13 and refraet it outwardly so as'to prevent the formation of darkened areas or non-illuminated areas along the side of the road Within the driving range of the headlights.

It will be observed that the'prisms'on opposite sides of the center of the lens are inclined in opposite directions, that is, the convex faces 17 are thus inclined, and from an inspection of FigSJ2 and 3, it will be noted that the prisms of the central group are fully convex. I

From an inspection of Fig. 4 it will be power ofthe prisms forming the central group being substantially constant.

In order to more specifically describe the particular embodiment of the'invention as shown an the accompanymgdrawmgs, but

without desiring .to limit the invention thereto, I have shown herein its commercial embodiment. The prisms indicated by a have their convex face formed with a radius of .176 inches, their flat face being .05 inches deep. The group b isxformed with a radius of .21 inches and a depth of .04 inches.

The group is 235 inches in radius and .032

inches in depth. The group d is .28 inches in radius with .03 inches in depth. The group c has a radius of .35 inches and a depth of .025

' inches. The group f has a radius of .415

, the radius of the prisms forming inches, while the depth is .02 inches, and the group 9 has a radius of .135 inches with a epth of 1/64th of an inch. Each of the prisms shown are made th of an inch wide in a lens having-a thickness of th of an inch. From the foregoing it will be apparentthat window through which the light rays reflected from the upper portion of thereflector may freely pass so as to throw a concentrated white bright light down the road. However,

the lateral spread of the light reflected from the side portions of the upper half of the reflector will. be intercepted by the prisms extending to the top of the lens on each side of the clear portion 19, such lateral diverging rays being refracted and directed toward the center of the beamso as to be superimposed thereon.

It'will be further noted that a reflector such as disclosed in m above-mentioned copending ap lication erialNo. 88,911, will project ,a su stantially crescent-shaped beam, the beam proj'ectedby the lower half of the reflector being inverted and superimposed upon the beam projected from the upper half. The principal crescent-shaped beam projected by the upper half of the reflector will flattened conical front and a marginal flange,

pass through the clear portion 19, of'the ,lens, while the inverted andsuperimposed crescent-shaped beam from the lower half of the reflector will be intercepted by the prisms rovided on the lower half of the lens, wherey the superimposed beam will be spread laterally so as to diverge from the axis of the beam for lighting'up the sides of the road and ditches.

Thus, in effect, there are provided two principal beams projectedlbythe reflector, one from the upper portion of the reflector and one from the lower,'said beams bein suerimposed one upon the other, the light the side my signature. ams from theupper portion freely passing 1 through the clear portion 19 of the lens so 5 as to give a bright drivin light at a distance down the road, whilet e beam from the lower portion of the reflector accornplishes the desired; spreading effect when this par-- ticular lens is employed in conjunction with the above-mentioned reflector. As above stated, however, the side prisms of the lens will act to gather in some of the extreme lateral rays and bend them towards the axis so as to increase the amount of light pro-"I5 jected down the road. In. addition to the above, the direct rays fromthe source-of illumination will be refracted b the prisms of the lower portion ofthe lens or spreading the saine over the surface'of the road immediatelyin front. of the vehicle.

The invention claimed is:

1. A lens for a headlight comprising a cen-' tral portion having a series of vertically-exries comprisin a central group of prisms for refracting lig tin opposite directions and effecting alateral distribution thereof, the upper ends of said prisms terminating substantially in a horizontal plane through thecenter of the lens, said lens beingw f ee from prisms above such horizontal plane fo freely emitting light therethrough without sub- I stantial refraction, and a plurality of verti- "cally extendin prisms on each side of said first-mentione group of prisms comprising means for refracting ight towards the axis of the lens.

2. A headlight including a concave'reflector, a source of .llght and a lens associated there-" with, said lens havin a series of vertical extending prisms exten ing thereacross, said series comprising a central group andagroup on. each side thereof, the prisms of said central group being materially shorter than the prisms of the side group to leave the upper central portion of said lens non-refractive, said prisms constituting means for refracting light projected from said reflector toward the vertical plane of the center of the beam and 1 10 for refracting a portion of the direct light from said source away from said plane.

3. A lens for a headlight comprising a the surface of said front having a series of 1 vertically extending prisms formed therein, the prisms at each side of the front extending substantially equal distances above and below the axis, said prisms being, constructed to throw the light toward said axis, andthe in- 2 termediate prisms havin their upper ends terminating below fine on s of the side prisms, said intermediate risms being symmetrical to spread the light horizontally in both directions.

In witness whereof, I have hereunto afiixed WALTER DARGY RYAN.

tending prisms extending thereacross,said se- .85 

